Steam generator furnace



Dec- 5 `1.944. J. P. BADENHAUSEN 2,364,044

STEAM GENERATOR FURNACE Filed Aug. 15, 1942 from pulverized coal has l the ash frompulverized fuel. 1

UHNlTED STATES -PAT ENT f ol=l=lcE STEAM GENERATOR FURNACE John Phillips adenhausen, Philadelphia, Pa. s `Application August 15, 1942, serial No. 454,952 7 claims.W (cl. 11o- 165) This invention relates to steam generators and more particularly to a steam generator having ,provisions for handling ash liberated by the com-` bustion of the fuel. In the generationxof steam with pulverized fuel, such as pulverized bituminous coal, a considerable quantity of ash is released by the burning of the coal and total quantity, upon continued operation, must be taken into consideration. This ash is usuallyin finely di-` vided form. It is the present practice to Vperrrlitlthe major portion of the" ash "`to collect onthe floor of the steamgenerator and remove thesame by raking and shoveling from time to time when a suflcient pile has `been collected. This mode l of handling the ash is not satisfactory and in-R terferes with the operation of the steam generator. Other portions of the ash `which are carried in the advancing stream of furnace gases are discharged from the stack, after passing through the induced draft fan. The discharge of ash into l the atmosphere, is objectionable. `Frequent re-` placement of the blades or rotorof the induced draft fan is required because of the erosive action of the ash thereon. None of the apparatus heretofore provided for the removal of the ash tory.

It is the principal object of the present invention to provide, for the removal ofthe'ash vfrom pulverized fuel burned in a steam generator. f It is a further object of the present invention to improve the operation of steam" generators It will, of course, be understood that the description and drawing hereinI are illustrative `merely,` and that `various `modifications and `changes may be made in the structure disclosed without departing fromthe spirit ofthe invention. l l

Referring more particularly to the drawing,

Athe apparatus of the presentinvention includes a steam generator Il] of any preferred type, hav. ing fuel burners II, to which fuel, such as pulverized bituminous coal,\is supplied from a pulverizer I2. A coal bunker I3 provides for a supply of coal for pulverization. l

An air preheater I4 is preferably `provided for receiving the hot gases of combustion' from the steam generator I 0 and absorbing `heat therefrom for preheating air for the delivery of fuel Eto the burners II and for the `combustionof the proven wholly` satisfacfuel introduced through the burners I I. The air heater I4 preferably has agas inlet I5 in communication with' the steam .generator I0 anda' gas outlet I6. The air heater I4 also has anair inlet Il and an air outlet I 8, the air outlet I8 being connected to suitable ducts I9, 20, one duct I 9 being connected to the burners II for supplying preheated air for introductionwith the fuel into the combustion chamber 2I and the other duct 20 being connected to the pulverizer I2 for supplying preheated air to the pulverizer I2 to entrain pulverized fuel and deliver the fuel in a preheatedair stream to the burners II. `A

bythe provision of apparatus which `may bel quickly and easily installed in the building of new `steam generators or which mai,7 be readily apf plied to existinginstallationsfor the removal of It is a further object of the present invention to provide in a simple and reliable manner for the separation and removal of ash released by the burning 4of pulverized fuel in a steam generator.

Other objects ofthe invention will be appar- Y ent from the annexed specification and claims.

The nature and characteristic features of the l inventionwill be more readily understood from l the following description,- takenv in connection with the accompanying drawing forming part hereof, in which:`

Figure'l is a diagrammatic view illustrating the present invention, partly in elevation `and partly in vertiallsection, the section `being taken approximately on the line I-I of Figure 2t Fig. `2 isa `horizontal sectional view taken approximately on the line 2-2 of Fig. l. i Y

fan 22` is provided in the fuel delivery line 23 from'the `pulverizer I2 to'the burners Il.

The steam generator I0 may be of any desired type but forthe purposes of explanation a specific form ofsteamgenerator is illustrated. The steam generator shown includes a combustion chamber 2| having atop wall 24 in which the burners II are mountedpa bottom Wall ,25 which serves as a collecting floor, a front wall 26, and side walls 21, with a rear baille 28 forming the rear wall of the combustion chamber 2|. The rear baille 28His terminated at a suitable distance above the bottom wall or 11001125 for permitting `the passage of gases therearound The steam ,generator IIl shown also includes an upper transsuitable riser and downcomer tubes extending therebetween for steam generation and circulation. The walls of the combustionwchamber 2| `are water cooled and provided.` with steam gen'- erating tubes extending a upwardly therealong. The side walls 2l` arelprovided with a bank of 35, 36 `and.downwardlyextendingibalies 31, 38

may be provided.; "In'they upward pass between the baille 28 and the baie 35, a superheater 40 For this purpose spaced upwardly extending baffles may be provided for superheating the steam lib-` erated in the steam and water drum 30,`l downward pass betweenA the bailiej35l and the baie 31, a bank of steam generating tubes 4|.

extending from the drum 3l to the drum 3U`I`n'ay" be provided. A bank of ldowncornertu'bes 42 may' be provided between the upper drum 30..,andthe,

lower drum 3| and in the downward pass between thebafe 36 and theballle 38.

' In accordance with the present, invention ythe 'gas outlet |6'of the airv heater ,|4 is connected by a suitableduct l44 to 'a dust` collector 45. The dust collector'45 may be ofv any` preferred .type for the separation of the gases of combustion and the ash and mayif desired, be of the single or multiple cyclone 4type and is preferably. constructed of suitable Amaterials to withstand the effectof .the temperature of thecombustionpgases upon their `discharge frornthe air heater |41; Thev lower part "ofthe dust ,collector 45.1 has an ash conveyor 46 connected' thereto, thel ash conveyor preferably being'of the screw conveyor type, and'driven by a conveyor motor 41. The gas outlet 'ofthe dust collector 45 is connected to an induced draftfanl 5,..whic`h is` driven by a motor 5|,1th`e Aoutlet of. the fan v5II-.being .lconnected by a 'suitableduct 52 toithe stack 53.`

'In accordance with the present inventiorralso,

the `steamgenerator I0 is provided withsuitable agitators'at "a plurality 'of`locations and preferablyv at" the places Where ash would normally havean opportunity to collect, such as, at the bottomfloor I25'of'A the combustion chamber 2| and at the floor`54 belowthe `air heater I4. 'The In the '15 agitators for lthe collecting space on the floor 25 of 'the combustion'bhamber 2| preferably include small pipes` or nozzles 6|J`at spaced ing l spaced intervals along 'each o'f the sidewalls of the air heater |4close to`fthejfloor 54. Y Pipes 64, having control `valves therein are Yconnected to the discharge pipes or nozzles "63.1

The pipes 6I and'fthe pipesi64are connected to a suitable source of iluid'under pressure, `such as'a tank 66, to which'airunderpressure of the orderof' 801to- 90'pounds per square inch is supplied by'aco'mpressor6'l. If desired, steam could be' supplied tothe pipes 6| and 64, and in place of the 'air Aif the sulphur content ofthe fuel was atfa low level. r

The modeof operation will now be pointed out. The steam generator I6 is `operated inthe customary manner, coalbeing supplied from the bunker I3 to the pulverizer I2. Air, preheated in the air heater I4 and delivered through the duct 20 tothe pulverizer I2, effects the delivery of pulverized coal andairthrough the duct 23 to the burners II. The coal is burned at the burners II, in the combustion chamber 2|, additional preheated air being supplied from the air heater I4 through the duct I3 to the burners I for combustion.

The rrelease of heat las radianty heat of combustion inthe,.,combustion chamber 2| effects steam generation inthe banks of wall tubes 32, 33, and.l 34. The gases of combustion passfrom thecombustion chamber 2| at the lower rear part thereof, through the upward pass 'between the rearwall baffle 28 and the baffle 35, and in contact 'with'the superheater tubes 4|) for superheating 'thestanf liberated in the steam and water drum 36. The gases of combustion then travel successively down through the pass between the baiiie 35 .andthe baiilel3`|=vin contact 'with the banks of tubes 4I for heating Athe same by convection`'upwardly through the pass between the baille-36 and thebaflle 31, and downwardly throughthe. passY between .the baffle 36 and the vbaille 38 Tin` contact`with the downcomer tubes 42.. The gases then travel through theair heater I4, and in passing therethrough preheat the air for combustion-. l

The vgases pass, from ,the combustion cham. ber 2| and in their travel move at a relatively highfvelocity,Y ofthe .order Vof two thousand to th1ee,.thousand .feet per. rninute. The velocity may. decreaseas the temperature decreases, to a `velocityof the Aorder of fteen hundred feet per minute. but 'the design and operation ofthe .steamgener'ator are preferably such that the gasesf moveat the higher velocity range. The flow of gases is maintained by the induced draft yfari .50.- whichrdischarges the'g'ase's throughthe ductf 52.,.to 'the stack l53.

Upon the combustion of the `pulverized'fuel .in the combustion chamber 25 the ash therein separates and Atendsin great'part to fall towards the floor 25. The ash particlesh'ave heretofore been permitted to collect on the floor 25 and have been removed therefrom from time to time by raking and sl'1'ov`elin'g.H In accordance with the present invention fluid underpressure is supplied continuously or, intermittently as desired and as required through the'pipes 6| to the small `pipes lor nozzles GII-'from whic'hfit is discharged at high velocityv across fthe floor-25. Any particles of ash'tending to' collect on the floor 25 are agitated vand swept ffrom the oor 25 and from above the floor 25upwar'dly into the stream of gases flowing from the combustion chamber 2|`. The ash particles'- are entrained and car.- ried onward with the moving stream of combustion gases in its travel. u i

The same character 'of agitation is efective` continuously or intermittently as desired 4and l.

required at the oor 54below the air heater I4. Any ash' particles ltending to `settlel onthe floor .541 are agitated an'dblown from the 'floor and from 'above the' floor'54 into the path ol?I gases passingupwardly through the air Jheater I4.

` The strea'mof gases with the ash'particles .entrained therein and carried therewith by `iloytationl pass into the'd'ust collector 45 where the gases andthe ash particles are separated. The 'ash .is withdrawn at thelower part of. the" dust collector 45.v and delivered by 'the lconveyor 46 for disposal. f The gases of combustion, freed of the solid ash' particles bythe dust collector 45` the noncombustible ash bustion of said coal, `and means for removing charged from the stack 1531", are free from` ash which would otherwise bedischargedinto` the atmosphere. All the ash is thus collected in a convenient manner ,aridlatl a"`convenient` loca- The gases of combustion; freedof s'olid tion. material, do not have any erosive action Von the rotor of the induced draft `fan Sil.`

I claim: p y i 1. In combination with a steamigenerator hav- Aing a combustion chamber withside walls` anda flat bottom wall, means in 'the upper part of said combustion chamber forgsupplying pulverized coal `for-combustion in said'chamber, said combustion chamberhaving a combustion gas discharge outlet at the lower part thereof, said bottom wall providing an ash collecting space for collecting the noncombustible ash released by the combustion of said coal, and means for removing from said steam generator the noncombustible as h released by the combustion of said coal and falling from the combustion gases, said ash removing means including nozzles spaced along said side walls for supplying air in a Aplurality of high velocity jets for agitatingthe falling ash particles whereby said ash particles are elevated from the bottom wall and entrained in the stream of gases generated in said combustion chamber for delivery from said steam generator with the combustion gases. i

2. In combination with a steam generator having a combustion chamber with side walls anda hat bottom wall, means for supplying pulverized coal for combustion in said chamber, said combustion chamber having a` combustion gas discharge outlet at the lower part thereof, said bot- `tom wall providing an `ash collecting space for collecting the noncombustible ash released .by the Icombustion of said coal, and means for removing from said steam generator the noncombustble ash released by the combustion of said coal and falling by gravity from the combustion gases, said ash removing means including nozzles spaced along said side walls for supplying air in a plurality of high velocity jets for agitating the falling ashparticles and elevating the same from the bottom wall for entrainment in the stream of gases generated in said combustion chamber and delivery from said steam generator with the combustion gases.

3. In combination with a steam generator having a combustion chamber with side walls and a nat bottom Wall,` means in the top wall of i said combustion chamber for supplying pulverized coal for combustion in said chamber, said combustion chamber having a` combustion gas discharge outlet at the lower part thereof, said bottom wall providingan ash collecting space for collecting released by the comfrom said steam generator the noncombustible i ash released `by the combustion of said coal and falling by gravity from the combustion gases,`

said ash removing means including nozzles spaced alongsaid side walls adjacent saidlat bottom wall for supplying air in a plurality` of high velocity jets for elevating the ash particles from the bottom wall for entrainment in the stream of gases generated in said combustion chamber and delivery from said steam generator with the combustion gases.

4. In combination with a steam generator having a combustion chamber with a top wall, side walls and a at bottom wall, means in the top `wall of said combustion chamber `for supplying pulverized coal for combustion insaidchamber,

said combustion 1lchamberha/'ing a cbmbustion 7 gas discharge outletfat the lower Vpart thereof,

,each of said sideywallsrfor said bottom "wallproviding an Aash collecting space for .collecting the noncombustible ashreleased by the combustion `of said coal, 4and means `for removing from said steam generator thenoncombustible ash released bythe combustion of A saidcoaland falling `by gravity from the combustion gases to the collecting space, saidash removing means including nozzles spaced 4alon'g supplying air ina plurality 'of high velocity `jets for agitating `the falling ashparticles, `whereby said ash` particles are elevated from the bottom Wall and entrained in the stream of gases generated in said combustion chamber for delivery from said steam genchamber having a combustion gas discharge outerator with the combustion gases.

5. In combination with a steam generator hav" ing a combustion chamber with a top Wall, a front wall, side walls, a flat bottom wall, upright bailies to the rear of said front wall providing a plurality of passes for Athe combustion gases, and a bottom wall at ,thev last of said passes, means for supplying pulverized coal for combustion in said chamber, said combustion let at the lower part` thereof, said bottom walls providing ash collecting spaces for collectingthe noncombustible ash released by the combustion of said coal, and means for removing from said steam generator the noncombustible ash released by the combustion of said coal and falling by gravity from the combustion gases to the collecting space, said ash removing means including nozzles spaced along certain of said walls for supplying air in a plurality of high velocity jets for agitating the falling ash particles whereby said ash particles are elevated from said bottom walls and entrained in the stream of gases generated in said'combustion chamber for degenerator with the comi livery from said steam bustion gases. i

6. In combination with a steam generator having a combustion gas outlet draft fan in said outlet conduit and a combustion chamber with a top wall, side walls and a bottom Wall, means in the top wall of said combustion chamber for, supplying pulverized coal from combustion in said chamber, said combustion chamber having a combustion gas discharge outlet at the lower part thereof, said bottom wall providing an ash collecting space for collecting the noncombustible ash released by the `combustion of said coal, and means for removing from said `steam generator the noncombustible ash released by the combustion of said coal and i falling by gravity from the combustion gases to the collecting space, said ash removing means including nozzles spaced along said side walls for supplying air in a plurality of high velocity jets for' agitating the falling ash particles wherebyv said ash particles are elevated from the oor and j entrained in the stream of gases generated in said combustion chamber for delivery from said steam generator with the combustion gases, and separator means in said gas outlet conduit beyond said combustion chamber for separating the entrained ash from the discharged combustion gases priorto` their passage to the induced draft fan. i

7. In combination with a steam generator having a combustion gas outlet conduit, an induced draft fan in said conduit and a combusti-on chamconduit, an inducedY -ber with. e iep-well@frentyyvalil VSide Wallsma at bottomfwall, upright'l `lpaffles 3 tol (the rear; of

said front Wall providing a pluialityoi passes]l for the combustion gases and a `bottomwzvall at:y the last. of-.said passes,l means yin the top wall .ofvsaid r combustion charnloen for supplyingv VApulxferized `ashr released bythe combustionI of said` coal and fallinglby gravity from :the` combustion gases lto aeg-enea the f collecting-Spena seid vasin V-reinovn el means including nozzles spaeed-aleng-fcertain ofesaid f walls -fer supplyirlefair apluraliiyfof high velocity iets ,forV agitating. ,the.falling ash particles whereby Isaid asl-1 particles-.k are elevated `from said bottom Walls and ,,entrained in the stream of gases generated in said fombustion chamber for. delivery frimel `said steam generator with vthe combustion gases, andi separator, means in vsaid gas outlet conduit beyond said combustion vchamber forseparating the Ventrained ash fromthe discharged combustion gases prior to' their passage to the induced draft fan,

JoHNPHiLLIPsBADENHAUsENL 

